Singapore has experienced a respite from the threat of haze this year due to the onset of wetter weather, despite the looming presence of the El Nino weather phenomenon.
Monsoon Patterns and Haze Trends
Singapore, along with Indonesia, undergoes two principal monsoon seasons: the north-east monsoon from end-November to March and the south-west monsoon from June to October. Between these two periods, transition phases or inter-monsoons occur. The Meteorological Service Singapore (MSS) highlighted that Singapore generally faces an elevated risk of transboundary haze during the south-west monsoon, when the region endures its dry season. During this time, fires in Sumatra or Kalimantan might result in smoke haze affecting Singapore.
Current Weather Updates
Though the El Nino phenomenon typically increases the likelihood of haze by intensifying dry conditions, Singapore has been relatively fortunate this year. MSS reported to The Straits Times that as Singapore moves into the inter-monsoon phase in late October and November, light and variable winds combined with a surge in showers make transboundary haze less probable. This is particularly true with the anticipated wet weather in the upcoming weeks.
Air Quality Monitoring
In 2023, Singapore witnessed unhealthy air quality just once, a first since 2019. On October 7th, the 24-hour Pollutant Standards Index (PSI) reading fluctuated between 67 and 123 by 9 pm, entering the unhealthy bracket (101 to 200). Thunderstorms have since arrived, with further rain predicted in the near future, which should help keep haze at bay.
Factors Influencing Haze
The majority of haze that affects the region originates from Indonesia’s peatland burning. When these peatlands are dried for agricultural purposes, they become highly combustible. While these fires are a significant concern, climate patterns such as El Nino can heighten dry conditions, thus escalating the risk of fires. During the north-east monsoon, Singapore’s risk of haze diminishes due to prevailing winds coming from the north or north-east, which steer clear of the burning hot spots.
However, MSS noted that during the inter-monsoon months, while the threat from transboundary haze remains low owing to the moist conditions, the light winds may occasionally lead to an accumulation of particulate matter. Such conditions can cause temporary hazy periods, usually during the night and early morning.
The Impact of Climate Phenomena
The past three years have been marked by recurring La Nina events, which, coupled with cooler temperatures, have resulted in prolonged rainy spells in the region, protecting Singapore from significant fire or haze incidents. However, most El Nino patterns usually wane between December and May, with successive La Nina events being more frequent than El Nino ones.
Simon Tay, the chairman of the Singapore Institute of International Affairs, emphasized the potential for El Nino and the Indian Ocean Dipole (a climate event inducing drier weather) to persist for multiple years, possibly increasing the haze risk in 2024 and beyond. Associate Professor Tay warns that considering the ever-present threat of climate change, the haze challenge is real and must be a global priority.
Conclusion
Singapore’s recent respite from the haze is a welcome relief for its residents. However, as global climate patterns evolve and shift, understanding and monitoring these changes will be vital for both immediate and long-term planning and responses.
Also learn about Clear Skies Ahead: Low Haze Risk in Singapore as Showers Expected.
